A stop of the aforenoted type and which is made from flexible plastic material is already known and comprises a square threaded screw intended to operate in conjunction with a threaded hole defined within the automobile bodywork. The position of the stop-surface of the stop, which corresponds for example to the alignment of a bonnet or a trunk lid with the other elements of the bodywork, can be adjusted by turning the stop, which is maintained at the desired position by means of the deformation which its thread undergoes when it is screwed into the corresponding hole.
The adjustment of this stop, that is to say the adjustment of the bonnet or the trunk lid with respect to the bodywork, requires a relatively long amount of time, even for experienced operators. A predetermined number of turns are actually necessary, and it is very rare that the correct number of turns will be made during the first attempt, so one or more further adjustments are subsequently necessary.